The most left-leaning candidate for City Council speaker says she would consider using eminent domain to seize homes that are in foreclosure from banks – a move that could leave taxpayers subsidizing the mortgages.

Melissa Mark-Viverito (D-Manhattan/Bronx), a close ally of Mayor-elect Bill de Blasio, said she was open to the proposal when asked about it during a forum in Queens Thursday night featuring five main contenders in the race for speaker.

“The idea of using eminent domain in a reverse way… as a way of seizing those properties from the bank as a way of making those homes affordable for people that want to stay in their communities I think is something we should look at,” said Mark-Viverito, a top contender for the powerful role. “I think it’s innovative, it’s creative … nothing should be off the table.”

A small town in California set off a firestorm of criticism after it began moving toward using eminent domain for hundreds of underwater mortgages.

In August, the Federal Housing Finance Agency warned municipalities against following suit – saying it would restrict federal loans to towns that do.

The other candidates for speaker said they weren’t familiar enough with using that type of eminent domain to weigh in or expressed strong reservations.

“It could be expensive for the city and I also think it’ll be a very long process – and I would question what happens to those properties in the years while you wait for the court proceedings,” said James Vacca (D-Bronx).

Mark Weprin (D-Queens) told The Post he didn’t think such an initiative would work economically.

“It would make it very hard to get loans from banks and it would probably raise interest rates on everybody else,” he said.

Dan Garodnick (D-Manhattan) and Annabel Palma (D-Bronx) were two the other top contenders at the forum, while a sixth candidate – Inez Dickens (D-Manhattan) – arrived at the very end.

The speaker will be selected by the 51 members of the Council, with no input from the public, in January.

It’s a position that currently sets the body’s agenda and dispenses millions of dollars in discretionary funds to each Council member’s district.